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Working with Hash Values

2:00 with Jason Seifer

So far, we've learned how to create and modify hashes and work with hash keys. Ruby provides several ways to work with the values in a hash as well. In this video, we'll explore different ways to work with the values in a hash.

Code Samples

For the examples below, we'll be working with this hash:

hash = { "item" => "Bread", "quantity" => 1, "brand" => "Treehouse Bread Company" }

To return an array of the values in the hash, we can use the values method:

hash.values

Which would return the following:

["Bread", 1, "Treehouse Bread Company"]

The has_value? method takes one argument and returns true or false if the value is contained within the hash:

hash.has_value?("brand")

That would return false since "brand" isn't a value. However, the following would return true:

hash.has_value?("Bread")

The values_at method takes several arguments and returns the hash values at the specified keys as an array:

hash.values_at("quantity", "brand")

That would return:

[1, "Treehouse Bread Company"]

Similarly, to hash keys, Ruby provides us methods for working with hash values. 0:00
Let's take a look of some of those now using WorkSpaces. 0:07
Okay, so I've just created a new ruby WorkSpace here and 0:10
here we are in the console. 0:14
Let's go ahead and launch an irb session and start working with hash values. 0:15
So let's create a hash to work with. 0:21
The item here is gonna be "Bread", quantity of 1 and 0:24
the brand is still gonna be "Treehouse Bread Company". 0:29
All right, so here is a hash to work with. 0:37
Now just like the method for looking at all the keys was called hash dot keys, 0:40
we have a similar method to look at all the values called values. 0:46
And that will return an array of all of the different values inside of the hash. 0:51
And again how we asked the hash if it had a key, and passed in an argument, 0:57
we can do the same thing to see if it has a value. 1:03
So we could say hash.has_value, and 1:06
then pass in a value it does not have the value "brand" because that's a key, but 1:09
let's see if it has a value for the number one which is the quantity and it does. 1:15
And we can also use the method value and pass in an argument. 1:25
It's pretty much the exact same thing, an alias under a different name. 1:30
If we wanted to get a couple values back from the hash, 1:36
we could use the values_at method and pass in the keys that we want. 1:39
We'll say we want "item" and "quantity", and 1:45
that will return an array of the values for the keys that we passed in. 1:48
Try practicing with hashes and hash values on your own now using WorkSpaces. 1:54

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